frivolous

Etymology

From Latin frīvolus (“silly, empty, trifling, frivolous, worthless”), with the ending modified to match -ous.

adj

1. Silly, especially at an inappropriate time or in an inappropriate manner.
2. Of little weight or importance; not worth notice; slight; trivial.
3. (law, said of a lawsuit) Having no reasonable prospect of success because its claim is without merit, lacking a supporting legal or factual basis, while the filing party is, or should be, aware of this.
   There is no easy definition for the phrase 'frivolous lawsuit,' but I imagine any claim for damages where the injuries are minimal or where the basis for the defendant's liability is hard to believe, might qualify as frivolous. August 31, 1996, Paul F. Waldner, President-Elect, Houston Trial Lawyers Association, “Viewpoints”, in Houston Chronicle
   One of the major cost drivers in the delivery of health care are these junk and frivolous lawsuits. 2005, Factcheck.org